The energy is the motivity of any activity. The development of human culture relates closely with the energy used, and dependence on the energy becomes stronger with the industrialization development. Nowadays, the energy has a close relationship with economics, politics, national defense, technology, traffic and environmental sanitation, and thus it is doubtless that the energy is important. The energy used by humans can be divided into renewable energy and non-renewable energy. The renewable energy is derived from the sun, the wind, the water, the tide and the temperature difference of the ocean. However, the non-renewable energy refers to the energy with limited storage and being dwindling such as the fossil fuel (for example, the coal, the oil and the natural gas) and the nuclear energy.
The water is a commonly used energy since the ancient times. In order to make use of the water energy, the motive force generated therefrom can be outputted through a proper transmission system. Unfortunately, the existing transmission systems have a constant receiving stress rather than a controllable receiving stress, and thus they can not be controlled according to actual needs. Therefore, the water energy can not be utilized in a best way, thereby unavoidably wasting the energy.
In order to overcome the drawbacks in the prior art, a controllable transmission system with a reasonable design is provided. The present invention overcomes the drawbacks in the prior art described above, and the summary of the present invention is described as follows.